Working with R-410A Refrigerant
Overview
R-410A is a high-pressure, environmentally safer refrigerant developed to replace R-22. It offers zero ozone-depleting potential and improved efficiency but requires specialised tools, components, and training due to its higher operating pressures
The Essentials Of Working With …
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Technicians must be certified and competent in safe handling and system servicing techniques specific to R-410A. Fujitsu General recommends following R-410A Safety and Handling Certification guidelines when installing, maintaining, or repairing any R-410A system.
Key Differences from R-22
| Aspect | R-22 | R-410A |
|---|---|---|
| Operating Pressure | 260 psig (high side) / 76 psig (low side) | 418 psig / 130 psig @ 120 °C condensing / 45 °C evap temp |
| Compression Ratio | 3.02 : 1 | 2.98 : 1 — slightly lower, higher efficiency |
| Oil Type | Mineral oil | POE (Poly-Ester) — highly hygroscopic |
| System Components | Standard | Must be 410A-rated (compressor, filter-drier, gauges, hoses, etc.) |
| Charging Method | Vapour or liquid | Liquid only, to prevent fractionation |
System Design and Component Requirements
Compressors:
R-410A compressors are built with thicker walls and higher-pressure relief valves (550–625 psig). Only use R-410A-rated compressors; never retrofit R-22 units
Metering Devices:
TXVs and capillary tubes must be sized approximately 15 % smaller than those used with R-22 systems.
Refrigerant Piping:
Lines must be clean, pressure-rated, and preferably new. If re-using existing R-22 lines, they must be flushed thoroughly to remove residual oil and debris.
Filter-Driers:
Use 600 psig-rated filter-driers. Replace the drier every time the system is opened, as POE oil absorbs moisture quickly
Brazing Materials:
Use high-temperature brazing alloys (Silphos or silver solder); never soft solder due to the higher system pressures.
Service and Safety Practices
Tools: Manifolds, hoses, recovery cylinders, and recovery machines must be R-410A-rated (DOT 4BA 400 / 4BW 400)
Leak Detection: Any HFC detector suitable for R-134a or R-407C can be used.
Recovery: Use approved recovery units and cylinders for high pressure refrigerants.
Evacuation: Pull down to 500 microns or lower. Replace filter-driers after every system opening.
Oil Handling: Store POE oil in sealed metal containers, minimise exposure to air, and wear gloves and safety glasses to prevent irritation.
Personal Safety:
Always wear eye and hand protection.
Never heat a refrigerant cylinder with an open flame.
Maximum safe cylinder temperature: 125 °F (52 °C).
Conversions and Retrofitting
Converting R-22 systems to R-410A is not permitted.
Differences in compressor design, operating pressure, and component rating make retrofitting unsafe and non-compliant
Summary
Working with R-410A requires:
Certified training in high-pressure refrigerant handling.
Correct tools and rated components.
Strict moisture and contamination control.
Proper evacuation, leak detection, and charging procedures.
These practices ensure safe operation, system longevity, and compliance with Fujitsu General service standards.